Cloud storage provides users with abundant storage space and make user friendly for immediate data access. But there is a lack of analysis on optimizing cloud storage for effective data access. With the development of storage and technology, digital data has occupied more and more space. According to statistics, 60% of digital data is redundant, and the data compression can only eliminate intra-file redundancy. In order to solve these problems, de-duplication has been proposed. Many organizations have set up private cloud storage with their unused resources for resource utilization.